DE 3 915 945 discloses such a woven fabric which, by means of different degrees of shrinking under heat treatment of the woven yarn, exhibits a bulkiness and a warm feel along with other desirable characteristics. This is predominately true, when a combined yarn is employed, whereby one portion thereof elongates under heat and another part shrinks under the same treatment (hereafter, termed “differential shrinkage”). The feel of such a weaving is better than weavings wherein threads are used which exhibit only shrinkable properties. In the case of the latter, the efficiency of production is negatively influenced by the shrinkage of the finished yarn. The situation can become even more disadvantageous, in that looping lengthens itself upon heat exposure and thereby, threads protruding out of the said loops are troublesome in successive processing. The difficulties can include splitting of the threads or loop snags in subsequent machine-centered processes.
On this account, in this cited DE 3 915 945, provision has been made that both of the differently shrinking yarns which form multi-filament yarns be joined together by vorticular turbulence, (hereinafter, “vortexed”) by means of which some 20 to 100 connecting nodes per meter are achieved. Furthermore, continuous filament threads were used for A and B, which threads, upon sizing, exhibit only a small difference in the change of length. When conventionally sized, both components show respective changes in length, whereas, in the present invention, the final length difference, brought about by the lengthening of the component A and the shrinkage of the component B, does not appear until the end of the heat treatment of the finished weave with air at a temperature of 160° C., at which time the bulkiness is also generated. In this manner, the threads, during the weaving operation are more easily manipulated than the conventionally combined threads, which shrink under heat treatment and, indeed, to different extents. The loopings, which immediately arise thereby, during the winding or the weaving, rub together and can entrap themselves in the loom equipment, whereby the woven formation and the workability of the fabric is substantially impaired.
In a case of the known procedure, limits are imposed, not only in the production, but also in the selection of the thread materials. More restrictions appear in the characteristics of the weaving, that is, in the feel of the fabric. For instance, only thread materials can be used, which, during the sizing procedure show somewhat the same shrinkage characteristics. However, the said thread material, during the end treatment of the woven fabric, must be such, that the elongation and the shrinkage so compensate one another, that the desired bulkiness is attained.
In order to assure a good, workability, vorticity becomes necessary, although the number of nodes per meter must not exceed 100, because otherwise, undesirable irregular places show up in the fabric along with a tendency for breakage of filaments of the multiple threads A.
Thus, a purpose of the present invention is to avoid these above stated disadvantages and to create a woven fabric which, both in its manufacture as well as in its properties shows an improvement above that which is now available. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
Surprisingly, experience has shown, that first, the number of the vortexed nodes, by means of which the components A and B are joined, and second, the number of the mutually crossover threads of the fabric system, must be in a complementary agreement. Thereby, considerably more vortexed nodes per meter in the yarn C become possible, without impairing the appearance of the weave. By means of the said nodes, loops, which occur by differential shrinkage, are more tightly bound together. Under these circumstances, there are fewer broken filaments appearing during the processing of the weave, and also, any tendency to stretch in later use is substantially reduced.
For a fault-free working of yarn in the weaving process, neither a vortexing of the yarn nor sizing is necessary, so that, in its manufacture, the woven fabric is clearly more economical and is less sensitive to the local environment. The fabric has the advantageous characteristic, in the Martindale abrasion examination regarding judgment of which color differences in accord with a grayness-standard, show fewer color variations from the original than standard comparison samples with lesser vortical node density. The woven fabrics show fewer “flamme” outcrops (randomly thickened twists), even though the yarn has not been vortexed. The reason for this is, that by the large number of nodes, the effect-yarn component A appears as though the threads would have been vortexed. In other words, the individual filaments lie somewhat transversely positioned due to the intensive vorticity and are no longer parallel. This provides a good covering of the shrinkage components.
In accord with a particular embodiment, the number of the vortexed nodes in relation to the number of threads in the transverse thread system lies in the range of ymin≧98+0.7x, wherein y=the number of nodes/meter in yarn C and x represents the number of threads per centimeter in the transverse arrangement, based on the finished woven fabric. The expression “yarn count (x)” is used throughout the present description to mean the number of threads per centimeter in the transverse thread arrangement. Therewith, advantageously, optimal conditions in regard to feel and appearance of the fabric is achieved. The woven fabric characterizes itself, not only in regard to its achieved volume, but also by the velvet-like feel brought forth by a uniformly structured surface.
By means of the features of the method according to aspects of the invention, the manufacturing costs are reduced by the elimination of the expensive sizing process and by the absence of sizing wash-out. Added to the economical measures is the elimination of reweaving of any non-vortexed yarns. Further details of the invention are described below with the aid of the attached figures.